I have been experimenting with using Yesod to throw together a web application or two. My experience so far has been broadly positive—if you like computers to check things for you, I recommend it.1 That said, watching the full chain of dependencies fly past was moderately entertaining:2

“In mathematics, a semigroup is an algebraic structure consisting of a set together with an associative binary operation. A semigroup generalizes a monoid in that there might not exist an identity element. It also (originally) generalized a group (a monoid with all inverses) to a type where every element did not have to have an inverse, thus the name semigroup.”

assuming you like deciphering compiler error messages when the computer says no, that is [↩]